Functional Properties of Two Different Molecular Forms of α2-Plasmin Inhibitor

I Clemmensen, S Thorsen, S Müllertz
1979 VIIth International Congress on Thrombosis and Haemostasis   unpublished
The α2-plasmin inhibitor in plasma exists in at least two molecular forms (1). One form (PB) binds to plasminogen-Sepharose. The other form (NPB) comprising around 0.4 of the total amount of the inhibitor in plasma does not bind to plasminogen-Sepharose. PB was purified by affinity chromato-graphy (1) while NPB was partially purified by conventional methods (2). Both inhibitor forms inhibited plasmin in a fast reaction and the change in catalytic concentration of plasmin with increasing
more » ... ations of both forms was a linear function. At identical active site concentrations of the two forms (titrated with pNPGB-titrated plasmin) PB produced a more marked inhibition of urokinase-induced fibrinolysis. Similanly PB produced a more marked decrease of the binding af Lys-plasminogen to fibrin than NPB. The results indicate that an equilibrium between the 2 forms may be important for the biological regulation of the inhibition of plasmin.
doi:10.1055/s-0038-1665782 fatcat:5p7z5saberh7tly6fp6ymcus7q